1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * HID raw devices, giving access to raw HID events.
4 *
5 * In comparison to hiddev, this device does not process the
6 * hid events at all (no parsing, no lookups). This lets applications
7 * to work on raw hid events as they want to, and avoids a need to
8 * use a transport-specific userspace libhid/libusb libraries.
9 *
10 *  Copyright (c) 2007-2014 Jiri Kosina
11 */
12
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/fs.h>
17#include <linux/module.h>
18#include <linux/errno.h>
19#include <linux/kernel.h>
20#include <linux/init.h>
21#include <linux/cdev.h>
22#include <linux/poll.h>
23#include <linux/device.h>
24#include <linux/major.h>
25#include <linux/slab.h>
26#include <linux/hid.h>
27#include <linux/mutex.h>
28#include <linux/sched/signal.h>
29#include <linux/string.h>
30
31#include <linux/hidraw.h>
32
33static int hidraw_major;
34static struct cdev hidraw_cdev;
35static const struct class hidraw_class = {
36	.name = "hidraw",
37};
38static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
39static DECLARE_RWSEM(minors_rwsem);
40
41static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
42{
43	struct hidraw_list *list = file->private_data;
44	int ret = 0, len;
45	DECLARE_WAITQUEUE(wait, current);
46
47	mutex_lock(&list->read_mutex);
48
49	while (ret == 0) {
50		if (list->head == list->tail) {
51			add_wait_queue(&list->hidraw->wait, &wait);
52			set_current_state(TASK_INTERRUPTIBLE);
53
54			while (list->head == list->tail) {
55				if (signal_pending(current)) {
56					ret = -ERESTARTSYS;
57					break;
58				}
59				if (!list->hidraw->exist) {
60					ret = -EIO;
61					break;
62				}
63				if (file->f_flags & O_NONBLOCK) {
64					ret = -EAGAIN;
65					break;
66				}
67
68				/* allow O_NONBLOCK to work well from other threads */
69				mutex_unlock(&list->read_mutex);
70				schedule();
71				mutex_lock(&list->read_mutex);
72				set_current_state(TASK_INTERRUPTIBLE);
73			}
74
75			set_current_state(TASK_RUNNING);
76			remove_wait_queue(&list->hidraw->wait, &wait);
77		}
78
79		if (ret)
80			goto out;
81
82		len = list->buffer[list->tail].len > count ?
83			count : list->buffer[list->tail].len;
84
85		if (list->buffer[list->tail].value) {
86			if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
87				ret = -EFAULT;
88				goto out;
89			}
90			ret = len;
91		}
92
93		kfree(list->buffer[list->tail].value);
94		list->buffer[list->tail].value = NULL;
95		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
96	}
97out:
98	mutex_unlock(&list->read_mutex);
99	return ret;
100}
101
102/*
103 * The first byte of the report buffer is expected to be a report number.
104 */
105static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
106{
107	unsigned int minor = iminor(file_inode(file));
108	struct hid_device *dev;
109	__u8 *buf;
110	int ret = 0;
111
112	lockdep_assert_held(&minors_rwsem);
113
114	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
115		ret = -ENODEV;
116		goto out;
117	}
118
119	dev = hidraw_table[minor]->hid;
120
121	if (count > HID_MAX_BUFFER_SIZE) {
122		hid_warn(dev, "pid %d passed too large report\n",
123			 task_pid_nr(current));
124		ret = -EINVAL;
125		goto out;
126	}
127
128	if (count < 2) {
129		hid_warn(dev, "pid %d passed too short report\n",
130			 task_pid_nr(current));
131		ret = -EINVAL;
132		goto out;
133	}
134
135	buf = memdup_user(buffer, count);
136	if (IS_ERR(buf)) {
137		ret = PTR_ERR(buf);
138		goto out;
139	}
140
141	if ((report_type == HID_OUTPUT_REPORT) &&
142	    !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
143		ret = hid_hw_output_report(dev, buf, count);
144		/*
145		 * compatibility with old implementation of USB-HID and I2C-HID:
146		 * if the device does not support receiving output reports,
147		 * on an interrupt endpoint, fallback to SET_REPORT HID command.
148		 */
149		if (ret != -ENOSYS)
150			goto out_free;
151	}
152
153	ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
154				HID_REQ_SET_REPORT);
155
156out_free:
157	kfree(buf);
158out:
159	return ret;
160}
161
162static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
163{
164	ssize_t ret;
165	down_read(&minors_rwsem);
166	ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
167	up_read(&minors_rwsem);
168	return ret;
169}
170
171
172/*
173 * This function performs a Get_Report transfer over the control endpoint
174 * per section 7.2.1 of the HID specification, version 1.1.  The first byte
175 * of buffer is the report number to request, or 0x0 if the device does not
176 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
177 * or HID_INPUT_REPORT.
178 */
179static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
180{
181	unsigned int minor = iminor(file_inode(file));
182	struct hid_device *dev;
183	__u8 *buf;
184	int ret = 0, len;
185	unsigned char report_number;
186
187	lockdep_assert_held(&minors_rwsem);
188
189	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
190		ret = -ENODEV;
191		goto out;
192	}
193
194	dev = hidraw_table[minor]->hid;
195
196	if (!dev->ll_driver->raw_request) {
197		ret = -ENODEV;
198		goto out;
199	}
200
201	if (count > HID_MAX_BUFFER_SIZE) {
202		hid_warn(dev, "pid %d passed too large report\n",
203			task_pid_nr(current));
204		ret = -EINVAL;
205		goto out;
206	}
207
208	if (count < 2) {
209		hid_warn(dev, "pid %d passed too short report\n",
210			task_pid_nr(current));
211		ret = -EINVAL;
212		goto out;
213	}
214
215	buf = kmalloc(count, GFP_KERNEL);
216	if (!buf) {
217		ret = -ENOMEM;
218		goto out;
219	}
220
221	/*
222	 * Read the first byte from the user. This is the report number,
223	 * which is passed to hid_hw_raw_request().
224	 */
225	if (copy_from_user(&report_number, buffer, 1)) {
226		ret = -EFAULT;
227		goto out_free;
228	}
229
230	ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
231				 HID_REQ_GET_REPORT);
232
233	if (ret < 0)
234		goto out_free;
235
236	len = (ret < count) ? ret : count;
237
238	if (copy_to_user(buffer, buf, len)) {
239		ret = -EFAULT;
240		goto out_free;
241	}
242
243	ret = len;
244
245out_free:
246	kfree(buf);
247out:
248	return ret;
249}
250
251static __poll_t hidraw_poll(struct file *file, poll_table *wait)
252{
253	struct hidraw_list *list = file->private_data;
254	__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
255
256	poll_wait(file, &list->hidraw->wait, wait);
257	if (list->head != list->tail)
258		mask |= EPOLLIN | EPOLLRDNORM;
259	if (!list->hidraw->exist)
260		mask |= EPOLLERR | EPOLLHUP;
261	return mask;
262}
263
264static int hidraw_open(struct inode *inode, struct file *file)
265{
266	unsigned int minor = iminor(inode);
267	struct hidraw *dev;
268	struct hidraw_list *list;
269	unsigned long flags;
270	int err = 0;
271
272	if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
273		err = -ENOMEM;
274		goto out;
275	}
276
277	/*
278	 * Technically not writing to the hidraw_table but a write lock is
279	 * required to protect the device refcount. This is symmetrical to
280	 * hidraw_release().
281	 */
282	down_write(&minors_rwsem);
283	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
284		err = -ENODEV;
285		goto out_unlock;
286	}
287
288	dev = hidraw_table[minor];
289	if (!dev->open++) {
290		err = hid_hw_power(dev->hid, PM_HINT_FULLON);
291		if (err < 0) {
292			dev->open--;
293			goto out_unlock;
294		}
295
296		err = hid_hw_open(dev->hid);
297		if (err < 0) {
298			hid_hw_power(dev->hid, PM_HINT_NORMAL);
299			dev->open--;
300			goto out_unlock;
301		}
302	}
303
304	list->hidraw = hidraw_table[minor];
305	mutex_init(&list->read_mutex);
306	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
307	list_add_tail(&list->node, &hidraw_table[minor]->list);
308	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
309	file->private_data = list;
310out_unlock:
311	up_write(&minors_rwsem);
312out:
313	if (err < 0)
314		kfree(list);
315	return err;
316
317}
318
319static int hidraw_fasync(int fd, struct file *file, int on)
320{
321	struct hidraw_list *list = file->private_data;
322
323	return fasync_helper(fd, file, on, &list->fasync);
324}
325
326static void drop_ref(struct hidraw *hidraw, int exists_bit)
327{
328	if (exists_bit) {
329		hidraw->exist = 0;
330		if (hidraw->open) {
331			hid_hw_close(hidraw->hid);
332			wake_up_interruptible(&hidraw->wait);
333		}
334		device_destroy(&hidraw_class,
335			       MKDEV(hidraw_major, hidraw->minor));
336	} else {
337		--hidraw->open;
338	}
339	if (!hidraw->open) {
340		if (!hidraw->exist) {
341			hidraw_table[hidraw->minor] = NULL;
342			kfree(hidraw);
343		} else {
344			/* close device for last reader */
345			hid_hw_close(hidraw->hid);
346			hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
347		}
348	}
349}
350
351static int hidraw_release(struct inode * inode, struct file * file)
352{
353	unsigned int minor = iminor(inode);
354	struct hidraw_list *list = file->private_data;
355	unsigned long flags;
356
357	down_write(&minors_rwsem);
358
359	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
360	while (list->tail != list->head) {
361		kfree(list->buffer[list->tail].value);
362		list->buffer[list->tail].value = NULL;
363		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
364	}
365	list_del(&list->node);
366	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
367	kfree(list);
368
369	drop_ref(hidraw_table[minor], 0);
370
371	up_write(&minors_rwsem);
372	return 0;
373}
374
375static long hidraw_ioctl(struct file *file, unsigned int cmd,
376							unsigned long arg)
377{
378	struct inode *inode = file_inode(file);
379	unsigned int minor = iminor(inode);
380	long ret = 0;
381	struct hidraw *dev;
382	void __user *user_arg = (void __user*) arg;
383
384	down_read(&minors_rwsem);
385	dev = hidraw_table[minor];
386	if (!dev || !dev->exist) {
387		ret = -ENODEV;
388		goto out;
389	}
390
391	switch (cmd) {
392		case HIDIOCGRDESCSIZE:
393			if (put_user(dev->hid->rsize, (int __user *)arg))
394				ret = -EFAULT;
395			break;
396
397		case HIDIOCGRDESC:
398			{
399				__u32 len;
400
401				if (get_user(len, (int __user *)arg))
402					ret = -EFAULT;
403				else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
404					ret = -EINVAL;
405				else if (copy_to_user(user_arg + offsetof(
406					struct hidraw_report_descriptor,
407					value[0]),
408					dev->hid->rdesc,
409					min(dev->hid->rsize, len)))
410					ret = -EFAULT;
411				break;
412			}
413		case HIDIOCGRAWINFO:
414			{
415				struct hidraw_devinfo dinfo;
416
417				dinfo.bustype = dev->hid->bus;
418				dinfo.vendor = dev->hid->vendor;
419				dinfo.product = dev->hid->product;
420				if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
421					ret = -EFAULT;
422				break;
423			}
424		default:
425			{
426				struct hid_device *hid = dev->hid;
427				if (_IOC_TYPE(cmd) != 'H') {
428					ret = -EINVAL;
429					break;
430				}
431
432				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
433					int len = _IOC_SIZE(cmd);
434					ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
435					break;
436				}
437				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
438					int len = _IOC_SIZE(cmd);
439					ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
440					break;
441				}
442
443				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) {
444					int len = _IOC_SIZE(cmd);
445					ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT);
446					break;
447				}
448				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) {
449					int len = _IOC_SIZE(cmd);
450					ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT);
451					break;
452				}
453
454				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) {
455					int len = _IOC_SIZE(cmd);
456					ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT);
457					break;
458				}
459				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) {
460					int len = _IOC_SIZE(cmd);
461					ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT);
462					break;
463				}
464
465				/* Begin Read-only ioctls. */
466				if (_IOC_DIR(cmd) != _IOC_READ) {
467					ret = -EINVAL;
468					break;
469				}
470
471				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
472					int len = strlen(hid->name) + 1;
473					if (len > _IOC_SIZE(cmd))
474						len = _IOC_SIZE(cmd);
475					ret = copy_to_user(user_arg, hid->name, len) ?
476						-EFAULT : len;
477					break;
478				}
479
480				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
481					int len = strlen(hid->phys) + 1;
482					if (len > _IOC_SIZE(cmd))
483						len = _IOC_SIZE(cmd);
484					ret = copy_to_user(user_arg, hid->phys, len) ?
485						-EFAULT : len;
486					break;
487				}
488
489				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) {
490					int len = strlen(hid->uniq) + 1;
491					if (len > _IOC_SIZE(cmd))
492						len = _IOC_SIZE(cmd);
493					ret = copy_to_user(user_arg, hid->uniq, len) ?
494						-EFAULT : len;
495					break;
496				}
497			}
498
499		ret = -ENOTTY;
500	}
501out:
502	up_read(&minors_rwsem);
503	return ret;
504}
505
506static const struct file_operations hidraw_ops = {
507	.owner =        THIS_MODULE,
508	.read =         hidraw_read,
509	.write =        hidraw_write,
510	.poll =         hidraw_poll,
511	.open =         hidraw_open,
512	.release =      hidraw_release,
513	.unlocked_ioctl = hidraw_ioctl,
514	.fasync =	hidraw_fasync,
515	.compat_ioctl   = compat_ptr_ioctl,
516	.llseek =	noop_llseek,
517};
518
519int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
520{
521	struct hidraw *dev = hid->hidraw;
522	struct hidraw_list *list;
523	int ret = 0;
524	unsigned long flags;
525
526	spin_lock_irqsave(&dev->list_lock, flags);
527	list_for_each_entry(list, &dev->list, node) {
528		int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
529
530		if (new_head == list->tail)
531			continue;
532
533		if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
534			ret = -ENOMEM;
535			break;
536		}
537		list->buffer[list->head].len = len;
538		list->head = new_head;
539		kill_fasync(&list->fasync, SIGIO, POLL_IN);
540	}
541	spin_unlock_irqrestore(&dev->list_lock, flags);
542
543	wake_up_interruptible(&dev->wait);
544	return ret;
545}
546EXPORT_SYMBOL_GPL(hidraw_report_event);
547
548int hidraw_connect(struct hid_device *hid)
549{
550	int minor, result;
551	struct hidraw *dev;
552
553	/* we accept any HID device, all applications */
554
555	dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
556	if (!dev)
557		return -ENOMEM;
558
559	result = -EINVAL;
560
561	down_write(&minors_rwsem);
562
563	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
564		if (hidraw_table[minor])
565			continue;
566		hidraw_table[minor] = dev;
567		result = 0;
568		break;
569	}
570
571	if (result) {
572		up_write(&minors_rwsem);
573		kfree(dev);
574		goto out;
575	}
576
577	dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
578				 NULL, "%s%d", "hidraw", minor);
579
580	if (IS_ERR(dev->dev)) {
581		hidraw_table[minor] = NULL;
582		up_write(&minors_rwsem);
583		result = PTR_ERR(dev->dev);
584		kfree(dev);
585		goto out;
586	}
587
588	init_waitqueue_head(&dev->wait);
589	spin_lock_init(&dev->list_lock);
590	INIT_LIST_HEAD(&dev->list);
591
592	dev->hid = hid;
593	dev->minor = minor;
594
595	dev->exist = 1;
596	hid->hidraw = dev;
597
598	up_write(&minors_rwsem);
599out:
600	return result;
601
602}
603EXPORT_SYMBOL_GPL(hidraw_connect);
604
605void hidraw_disconnect(struct hid_device *hid)
606{
607	struct hidraw *hidraw = hid->hidraw;
608
609	down_write(&minors_rwsem);
610
611	drop_ref(hidraw, 1);
612
613	up_write(&minors_rwsem);
614}
615EXPORT_SYMBOL_GPL(hidraw_disconnect);
616
617int __init hidraw_init(void)
618{
619	int result;
620	dev_t dev_id;
621
622	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
623			HIDRAW_MAX_DEVICES, "hidraw");
624	if (result < 0) {
625		pr_warn("can't get major number\n");
626		goto out;
627	}
628
629	hidraw_major = MAJOR(dev_id);
630
631	result = class_register(&hidraw_class);
632	if (result)
633		goto error_cdev;
634
635        cdev_init(&hidraw_cdev, &hidraw_ops);
636	result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
637	if (result < 0)
638		goto error_class;
639
640	pr_info("raw HID events driver (C) Jiri Kosina\n");
641out:
642	return result;
643
644error_class:
645	class_unregister(&hidraw_class);
646error_cdev:
647	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
648	goto out;
649}
650
651void hidraw_exit(void)
652{
653	dev_t dev_id = MKDEV(hidraw_major, 0);
654
655	cdev_del(&hidraw_cdev);
656	class_unregister(&hidraw_class);
657	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
658
659}
660